The present invention relates to a full width power loom, in particular for producing flat woven paper machine webs or other technical fabrics with warp and weft threads, for example with widths of more than 6 meters, which has a sley reciprocatable in direction of warp threads.
The present invention also relates to a method of operating a power loom as well as to a method of moving guiding elements for a projectile of power looms with reciprocatingly swinging sleys.
Power looms for producing flat woven paper machine webs and similar technical fabrics, which have widths of 6-12 meter and are subjected to high warp tension and sley impact forces up to 5 tons/meter of weaving width are special power looms and are not comparable with the class of the textile weaving machines. Characteristic features of the textile weaving machines are their small weaving width, their high shooting number per minute and their light construction corresponding to these conditions. They are characterized by a drive for the sley which is conventional for this weaving machine and provided through a swinging shaft which carries a sley support for supporting the sley and which moves with the sley support in an angle synchronous member. The drive of the swinging shaft is performed in these machines through a cam transmission shown in FIG. 10. While the above described special power looms operate in correspondence with the current technology with a shooting number of approximately 50 shots/minute, the textile power looms run with mechanical shooting action of more than 100 shots/minute and power looms with pneumatic shooting process run with up to 1,000 shots/minute and more.
An important reason for the relatively low shooting numbers in the special power looms is that the shooting is performed by so-called gripper shuttles, in which due to their dimensions and their mass which must be not only accelerated but also mounted reliably and in accurate positions relative to the stand do not permit higher shooting numbers.
It has been attempted to miniaturize the gripper shuttles. However, the respective attempts are limited by the fact that the gripper shuttles due to their dimensions and reduced weight when they are shut through the shed become instable and in extreme cases fly out of the shed. One of example of such a miniaturized gripper shuttle is disclosed in the German patent DT 15 35 561. The instable shuttle flight limits also the shooting speed and thereby the productivity increase of these machines.
The German patent DE-A1 32 42 121 discloses that the disadvantages of the instable shuttle run can be eliminated when the guiding elements for the shuttles are provided. While the construction disclosed here prevents flying out of the shuttles, this system however has disadvantages in that the shuttles roll along the warp threads of the undershed which is supported on the sley. In the case of a not clean undershed or overpacking of the web blade, or in other words when not all warp threads of the Undershed are located exactly near one another, but partially overlap one another, this acts in a breaking fashion on the shuttle and also influences the productivity increase of the machine.